Author Archives: Marjolijn

Today 2 papers of our group were published online! This papers are the result of a successful collaboration between the University of Groningen, NIOZ and Radboud University, The Netherlands The first study by Els van der Zee et al. demonstrates that food web structure and complexity can be fundamentally shaped by habitat-modifying species. This works through facilitation rather than trophic interactions […]

Within the Dutch Caribbean, green and hawksbill turtle rookeries and foraging grounds are found. Green and hawksbill turtles have been decimated by human exploitation and habitat degradation, calling for knowledge of population structure and demographic history. Here we investigate migration patterns in these highly migratory species and evaluate current population status. In other words: How many turtles were there […]

Last week we* successfully placed a satellite transmitter on a big green turtle female after she nested at Little Curacao’s turtle beach. The signals of the ARGOS satellite are updated hourly and I am very happy to report that this female is swimming very fast in the direction of Nicaragua 1050km in the first 10 […]

I am Fee, the first master student who will monitor the exclusion cages in Lac Bay on Bonaire for three months. I arrived two weeks ago. My main research questions are: How does turtle grazing affect the productivity of and competition between the native T. testudinum and invasive H. stipulacea in Lac Bay, and what […]

4 sub-adult green turtles that we caught in Lac Bay are now equipped with satellite transmitters to study their movements and use of the seagrass meadows, (see more photos below). The greens that forage in the shallow Lac Bay area are typically sub-adults. We selected some of the biggest turtles that forage here, to not […]

Two weeks ago we arrived on Bonaire. Since then we worked non-stop and we made great progress! The first thing we did was to set up a turtle exclosure experiment on the seagrass beds in Lac Bay, after Funchi (STCB) and Sabine Engel (STINAPA) kindly showed us all the suitable seagrass areas. The native dominant […]

I am very excited to finally start our fieldwork on sea turtles and seagrass in the Bonaire, Aruba and Curacao! What started as a proposal (initiated by Lisa Becking and me) in August 2013, finally resulted in a research project May 2015 entitled “Ecology and conservation of Green and Hawksbill turtles in the Dutch Caribbean”. […]

Who eats who in the Wadden Sea? We collected 12000 samples in one of the largest dbases of stable isotope samples. Using these samples we found that the energy in the Wadden Sea (primary production) is mainly provided by the production of benthic algae (diatoms) on the tidal flats. Papers about this are underway but […]

The Wadden Natuur kaart (Wadden Sea Nature Map) is now online: this is one of the publications of the Waddensleutels project on which I worked in the last 2+years. You should definitively explore and test it. For example; activate the benthos hotspot layer (upper left) and see which areas are most interesting as foraging areas for […]

The Waddensleutels project finished 16 april 2015 with a symposium in Leeuwarden, and with that also my 1st post-doc project. Topics here were: Which measures should we take to increase the area of musselbeds in the Dutch Wadden Sea & what is the current foodweb stucture and state (and how is this affected by the […]

Posts navigation

Marjolijn Christianen

Assistant Professor @WUR, Blogs about fieldwork & events during her current research projects on sea turtles in the Dutch Caribbean, on food webs and ecosystem restoration in the Wadden Sea & about her completed PhD project on seagrass & green turtle grazing. She also provides practical info on her previous fieldwork site: Derawan in East-Kalimantan, Indonesia